Presented at the HMX IDECool Launch for Channel Partners, Pune, 10-11 February 2017, "Trends in Comfort Cooling" discusses the history of cooling, the contribution of cooling to global warming, trends, and more. Visit http://ategroup.com/hmx/why-evaporative/ to learn more or e-mail us at contactus(at)ateindia(dot)com.
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Presented at the IDECool Launch for Channel Partners, Pune, 10-11 February 2017
Trends in Comfort Cooling
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A Look Back
1840s First mention of “active cooling systems”
1915 Carrier Corporation founded (now a part of UTC --- United
Technologies)
1890s Air blown over stored ice or pipes with pressurized liquid that
absorbed heat to provide comfort
1902 Sackett & Wilhelms, Brooklyn, New York, install a system to control
the humidity in a printing factory. Designed by Willis Carrier.
Silk mill
Drug firm
Gillette factory to manufacture safety razors
1920s Comfort in public spaces like cinemas and department stores
Larger sizes, more standard products, refrigerants (CFCs, HCFCs),
……
Sources multiple including The Economist, Stan Cox’s Losing Our Cool
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Fast-Forward Today
Rising CO2 levels in the atmosphere leading to global warming
Tied to the rising energy consumption all over the world and burning of
fossil fuels
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India’s Growth Fueled by Oil
If India’s economy grows as expected, it will consume several times more energy in
next decade ….
Sources Energy Statistics 2012, Central Statistics Office, Government of India
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Cooling Contributes to Global Warming
About 35-40% of the energy consumed by commercial and residential buildings
As much as 50% of the energy consumed in buildings is used for cooling
India will construct 2x more building area in next 15 years than in last 60 years!
Source: Energy Conservation and Commercialization [Eco-II], 2010
Huge potential in India to set a new energy-
efficient and greenhouse gas-sensitive paradigm
in “cooling for comfort”
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Trends in Comfort Cooling
• Green Refrigerants
• Understanding Comfort and Models for Comfort
• Quantifying comfort: building modelling and simulation
• Comfort through Indoor Air Quality (IAQ)
• Benefits derived from Comfort
• Energy-efficient comfort cooling
• Building architecture to promote comfort
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Refrigerant Type Global Warming Potential or GWP
(100 year, Assessment Report 4, 2007)
R410A – R32/R125 (50/50) HFC 2088
R22 – chloro difluoro methane HCFC 1810
R134A – chloro difluoro methane HFC 1430
R32 – methylene fluoride HFC 675
R290 – propane HC, “natural” 3.3
R1270 – propylene HC, “natural” 1.8
R744 – carbon dioxide “natural” 1
R717 – ammonia “natural” 0
Green Refrigerants
Agreement at Montreal Protocol (2016)
• Developed countries to reduce using HFC from 2019
• China to reduce using HFC from 2024
• India to reduce using HFC from 2028
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Comfort
“That condition of mind which expresses
satisfaction with the thermal environment
and is assessed
by subjective evaluation.”
ASHRAE Standard 55
Thermal Environmental Conditions for Human Occupancy
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Comfort
Human body produces 100-150 W of heat under normal
conditions and moderate activity level
This heat must be “dissipated” in order to
maintain constant body temperature
Heat in Heat out
When human body attains constant temperature, it is said to be “comfortable”
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Comfort in Engineering Terms
Human body can lose heat (“dissipation”) by various mechanisms
• Conduction to air due to difference between temperature of air in contact with that of
the human body
• Convection to air due to temperature difference and air movement
• Radiation to surrounding walls due to difference in temperature of surfaces not in
contact
• Evaporation driven by moisture levels in air
Which is more important and when?
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Comfort in Engineering Terms
Evaporation
Convection
and radiation
28 °C
Dry Bulb Temperature
HeatLoss
Source Heating, Ventilation, Air Conditioning Guide 37 63
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Adaptive Model of Comfort
ASHRAE limits valid for :
• Operable windows
• No mechanical cooling
• Metabolic rate 1-1.3 met
• Clothing Level 0.5-0.7 clo
IndoorOperativeTemperature
f(IndoorTemperature,MRT)
Prevailing Mean Outdoor Temperature
(Moving average of mean daily temperature, 7-30 days,
single value for each day of year)
10 °C 33.5 °C
31.7°C
24.7°C
ASHRAE 55-2010, Section 5.3
ASHRAE Software Tool for Comfort
http://smap.cbe.berkeley.edu/comforttool
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Adaptive Comfort is Applicable to India
ASHRAE limits
• Operable windows
• No mechanical cooling
• Metabolic rate 1-1.3 met
• Clothing Level 0.5-0.7 clo
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Building Energy Modelling (BEM)
• Computer-based simulation of energy performance of a building
• Process of using a computer to build a virtual replica of a building
• Focus on energy consumption and life-cycle costs
• Building simulation is a method to quantitatively predict the future and
thus has considerable value
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BEM: Scope
Building simulation is commonly divided into two categories
• Load Design
• Energy-Analysis
Load Design is used to determine
• Air conditioning loads
• Volumetric air flow requirements
• Equipment capacities
Energy Analysis or Energy Modelling is used to (building simulation when energy is
involved is commonly referred to as Energy Modelling)
• Predict the monthly & annual energy consumption and bills.
• Compare and contrast different efficiency options
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BEM: Benefits
For same degree of comfort:
• Compare different building designs including passive constructions
• Identify major contributors to heat load in the building
• Compare different technologies and HVAC configurations
• Evaluate equipment capacities based on unmet hours
• Detailed hourly results
• Compare annual energy consumption data of various equipment
• Evaluate energy savings
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Building Energy Modelling
6149 hours outside comfort envelope 3758 hours
STANDARD CONSTRUCTION
… WITH REFLECTIVE and Low-EMISSIVITY
SURFACES
Case A.T.E. factory, Sari, Sanand taluk, Gujarat, 40,600 ft2 floor area
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BEM: Example
Configuration
Machine Size, cfm
(300 unmet hours at 28 °C)
CapEx
Rs.
OpEx
Rs. / year
NPV *
Rs.
Ambiator 122,000 3.66 Mn 2.07 Mn - 23.4 Mn
Ambiator + Paint 85,000 2.96 Mn 1.56 Mn - 17.9 Mn
Ambiator + Paint + Film 80,000 3.29 Mn 1.5 Mn - 17.7 Mn
* Discount rate 10%, energy at constant Rs. 6/kWh, paint @ Rs. 10 / ft2 replaced every 3 years, film @ Rs. 12 / ft2 replaced every 5 years
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Comfort through Indoor Air Quality (IAQ)
Parameters include:
• Volatile organics (VOCs)
• Particulate matter (PM2.5 , PM10)
• Biological contaminants
• Chemical contaminants (NOx, SOx)
• Carbon dioxide (CO2) mainly due to that exhaled by humans
Two methods to maintain IAQ
• Incorporate multiple levels of filtration
• Use fresh air defined by ASHRAE standards for different applications
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Benefits Derived From Improved Comfort
• 12% higher productivity possible by
maintaining comfort conditions
Sharma & Chandwani 2016 IIM Ahmedabad
study on Indian factories
• 0.2% rise in productivity for each
1°C drop in temperature
Adhvaryu et al. 2014 U Michigan on 29
garment factories in Bangalore
• 8.8% higher operator performance
at a call centre by raising fresh air
supply from 9.8 to 22.7 l/s-person
(at indoor temperature 24.5°C)
Tham et al. 2003 call centre in Thailand
• Inadequate fresh air propagated
tuberculosis to health care workers
Menzies et al 2000 study on 17 Canadian hospitals
• US soldiers got more coughs and colds
if they slept in air-conditioned barracks
than if they slept in tents and
warehouses
Richards et al 1993a on soldiers stationed in Saudi
Arabian desert during Gulf War I
• Common colds in crowded dormitories
fell by 85% by raising fresh air to 5 l/s-
person from 1 l/s-person
Sun et al. 2011 3700 students in 1500+ dorm rooms
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Contact us
For more information:
A.T.E. Enterprises Private Limited (Business Unit: HMX)
Plot no 113 & 114, Phase III,
Peenya Industrial Area, Bengaluru - 560 058,
India.
Email: ambiator@hmx.co.in
Phone: +91 80 - 2372 1065 / 2372 2325
Or visit us: www.ategroup.com/hmx